1. Field of the Invention
The present invention relates to a thermal transfer printer and, in particular, to a thermal transfer printer which is capable of printing on a variety of types of printing paper and which can perform a printing with high image quality comparable to that of silver salt photographs by using a specific kind of printing paper.
2. Description of the Related Art
Thermal transfer printers are generally used as the output apparatus for computers, word processors or the like due to their high quality in printing, their low noise and low cost, ease of maintenance, etc. In a thermal transfer printer, printing paper and an ink ribbon coated with a desired kind of ink are supported in front of a platen, and the ink ribbon is delivered as a thermal head with a plurality of heat generating elements arranged thereon is reciprocated along the platen together with a carriage, with the heat generating elements arranged on the thermal head being selectively caused to generate heat on the basis of printing information to thereby print a desired image in the form of a character, etc. on the printing paper.
Two types are known of the conventional thermal transfer printer: one which prints on printing paper by using an ink ribbon consisting of a plastic base film coated with a hot melt ink (a hot melt ink ribbon) and one which prints on printing paper by using an ink ribbon consisting of a base film coated with a hot sublimation ink (a hot sublimation ink ribbon).
Of these two types, the type of thermal transfer printer which prints on printing paper by using a hot melt ink ribbon (hereinafter referred to as a "hot melt type thermal transfer printer") is useful in that it allows printing on a variety of kinds of paper, such as ordinary paper, cardboard and postcards.
The other type, which prints on printing paper by using a hot sublimation ink ribbon (hereinafter referred to as a hot sublimation type thermal transfer printer") provides a high quality printed image comparable to silver salt photographs by using a specific kind of surface-treated paper.
The hot melt type thermal transfer printer and the hot sublimation type thermal transfer printer have been individually put into practical use as different types of thermal transfer printers due to the differences in the properties of the inks used in them.
As stated above, the hot melt type thermal transfer printer and the hot sublimation type thermal transfer printer have been individually put into practical use, so that when both the general type of printing on ordinary paper and the high-quality printing to produce an image comparable to silver salt photographs are needed, it is necessary to use two different types of thermal transfer printers, i.e., a hot melt type thermal transfer printer and a hot sublimation type thermal transfer printer, which would involve a large space for installation and an increase in cost.
Thus, there is a demand for a thermal transfer printer which is capable of both printing using an ink ribbon coated with a hot melt ink and printing using an ink ribbon coated with a hot sublimation ink.